Users of grinder/polishers and dispensers typically include manufacturers of metals, polymers, ceramics or other materials used for building many different types of products. Metallographic laboratories and production-support laboratories or quality-assurance/quality-control laboratories use sample-preparation systems to grind materials to a near-mirror-like finish before examining the microstructure of the materials to assess adherence to quality-control standards. Fluid dispensers are used for dispensing abrasive solutions onto a rotating platen or cloth used for grinding/polishing the material samples.
Conventional solution-dispensing systems typically have various shortcomings associated with them. For instance, a conventional solution dispenser, named Multidoser, is available from Struers USA, which is headquartered in Denmark; has  an office in Westlake, Ohio; and was recently purchased by Roper Industries of Bogart, Georgia. The Multidoser can be purchased in either a 3-bottle version or a 6-bottle version. The 3-bottle version can be used to dispense up to 3 solutions simultaneously. Similarly, the 6-bottle version can be used to dispense up to 6 solutions simultaneously. The 3-bottle version cannot, however, be upgraded to the 6-bottle version without significant effort. Regardless of which version is purchased, the Multidoser is sold in a cabinet large enough to accommodate 6 solution bottles. Under some circumstances, therefore, the Multidoser will waste laboratory space near a grinder/polisher.
A solution-dispensing system that provides more flexibility in allowing users to incrementally add solution-dispensing capacity, allows users to apportion bottles of solution flexibly between any number of grinder/polishers, and uses space efficiently would, therefore, be desirable.
A memory-and-control unit, called RotoCom, is available from the makers of the Multidoser. The RotoCom can be used for programming the Multidoser and a grinder/polisher to perform multi-step materials-preparation methods, including multiple-step dispensing methods performed in synchronization with multiple-step grinder/polisher methods. Some grinder/polishers, though, store pre-defined multiple-step grinding/polishing methods. This renders programmability of a grinder/polisher by a unit separate from the grinder/polisher unnecessary. This unnecessary functionality, namely, programmability of a grinder/polisher from a unit separate from the grinder/polisher, undesirably increases the cost associated with adding fluid-dispensing programmability by requiring a customer to purchase grinder/polisher programmability even though the customer wants to add only fluid-dispensing programmability.
A more cost-effective way of adding programmability to a fluid-dispensing system would therefore be desirable. 
Single-bottle fluid dispensers are well known in the art. Some of these conventional single-bottle fluid dispensers do not, however, communicate with, and/or operate in synchronization with, other fluid dispensers. When using several of these conventional single-bottle fluid dispensers together, each dispenser would have to be manually started and manually stopped for each fluid-dispensing step. In addition to being inconvenient to the user or operator of the fluid-dispensing system, manually stopping multiple single-bottle dispensers wastes abrasive solution, which is expensive. Fluid dispensers that cannot automatically stop dispensing fluid after an operator-selectable dispensing duration undesirably create a situation in which the operator needs to be present solely to manually stop the dispenser. If the operator wants or needs to walk away from the grinder/polisher during operation and the dispenser cannot be programmed to automatically stop dispensing fluid, the dispenser may continue dispensing fluid longer than desired thereby wasting fluid. Further, without such an automatic shutoff, the operator might have to stop in the middle of a step, and repeat that step later, wasting expensive abrasive and time. Being able to specify when the dispenser will automatically shutoff would therefore be desirable.
A different type of single-bottle fluid dispenser can be coupled to another dispenser that issues commands to the single-bottle fluid dispenser to start dispensing, stop dispensing, set a dispensing rate, and set a dispensing duration. This type of single-bottle fluid dispenser, however, does not run in a stand-alone mode in which it is not under the control of another dispenser. A cost issue therefore arises because a more expensive programmable unit is needed for controlling this type of single-bottle dispenser. Further, this kind of single-bottle fluid dispenser does not communicate any information, such as a bottle identifier, back to the dispenser that is controlling it. This lack of bi-directional communication limits the controller's ability to detect error conditions and to control the single-bottle dispensers in ways that require bi-directional communication. 
Accordingly, a space-efficient single-bottle fluid dispenser capable of running in stand-alone mode and communicating bi-directionally with, and/or running in synchronization with, one or more other fluid dispensers would be desirable.
Conventional fluid dispensers typically do not monitor the volume of fluid in the dispenser bottles or provide a warning to an operator when the fluid level becomes low. Monitoring fluid levels and providing this type of warning would be desirable because, if a bottle runs out of fluid during a grinding/polishing operation, the samples could easily be ruined. This could be very expensive because new specimens might have to be obtained, the entire grinding/polishing process might have to be restarted from the beginning, and production go/no decisions could be delayed. In addition, heat could be generated that might damage the expensive consumable surface, to which the abrasive is applied, thereby requiring replacement.